Down-the-hole (DTH) drills are used for oil drilling, natural gas, geothermal drilling, and other deep earth penetration applications. For nearly any drilling method, a casing is inserted into well bore. During cementing operations, it is desirable to centralize the casing in the well bore, assuring a competent cement seal. Bow spring centralizers are the primary method of centralizing the casing. They are designed to be easily attached to the casing as it is run, and have a limited centralizing force to because of the tradeoff required for minimizing insertion drag. The design features that make them easy to use also contribute to their limitations, namely a limit to the deflection force generating capabilities. This can compromise the cement job due to variation in cement thickness caused by a lack of concentricity between the casing and the well bore. Additionally with modern horizontal and slope drilling and casing, the centralizers must exert enough force to support the weight of the casing.
What is needed is a centralizer system and method that overcomes the limitations of the prior art.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.